Apparatus for electrolyzing fused salts



July 7, 1925. 1,545,384

E. A. ASHCROFT APPARATUS FOR ELECTROLYZING FUS EiD SALTS Filed May 7, 1923 5 Sheets-Sheet 1 July 7; 1925.

E. A. ASHCROFT APPARATUS FOR ELECTROLYZING FUSED SALTS Filed May '7, 1925 5 Sheets-Sheet 2 N m N Fig. 3.

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E. A. ASHCROFT APPARATUS FOR ELECTROLYZING FUSED SALTS 5 Sheets-Sheet 4' Filed May '7, 1923 July 7, 1925. 1,545,384

- E. A. ASHCROFT APPARATUS FOR ELECTROLYZING FUSED SALTS Filed May '7, 1923 5 Sheets-Sheet 5 x Fly. 5.

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5 of London, England, and of W Patented an 7, 1925,

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, abou ARTHUR Asnc'aor'r, or nom on', ENGLAND.

nuance son mncrnonyzme FUSED saws.

- Applicationnled Kay 7,.

. To all whom it may concern:

Be it known that LEDGAR ARTHUR As a CROFT, a subject of the King of Great Britain, 1

residing at 32 Liverpool treet,l, in the city a e, near Ashburton, in the county of Devon, ngland, have invented new and useful Improved Apparatus for Electrolyzing Fused Salts,

of, which "the following is a specificatiom 1 present invention and how ber of the aforesaid My present invention consists in improvements upon, or modifications of, the invention described and claimed under my application Serial No. 551,306, for Letters Patent dated the 10th day of-April A. D. 1922,

"my present improvements, or modifications, providing for effecting the electrolysis of the "fused salts, or compounds, in a very efficient manner, and in an apparatus which may consist of, or comprise, any desired number of multiple-couple electrolyzers, or piles, in accordance with my. said application Serial No. 551,306, A. D. 1922, grouped together, or combined, in one apparatus, or in a number of connected apparatus, the combination constituting one compound electrolyzer of high voltage.

I Will further describe the nature of my it may be performed with reference to the accompanying drawings wherein Figure 1 is a longitudinal vertical section and Figure 2 is a plan (with the cover removed) of apparatus in accord- A ance with my present invention, whilst Figu're'3 1s a section (drawn to a larger scale)l of. portions of superposed electrodes whic tudinal vertical section on the lines-w :0,-

Figures 4: and 6 respectively and a transverse. section on the ines m Figures 4 and 5,.of a modification wherein are arranged vertically. v Referring first to Figures 1 and 2 the apparatus therein illustrated consists of a nummultiple-couple electrolyzers, or piles, each comprising any desired number of electrodes, or plates, B, B B (say, for example, as shewn in the drawings, twelve piles, each consisting of say twenty-one electrodes, or plates, that is,of twenty couples) grouped together in a tank A, and insulated from each other and at the electrodes silica, or other suitable -side sheets being preferably bottom, for instance by sheets a of fused material, fitting closey against the electrodes, or, plates B, B and against each other, the end and kept in position and pressed against the edges of the electrodes, or plates, by a filling of insulating material; such, for example, as the silica beads, shewn at a in Figure 1. The electrodes, or plates B, B and B are preferably composed of compressed carbon, or graphite, and are separated from one another by insulating supports; such, for example, as rods 6 of fused silica. Each pile of electrodes, tral graphite connection E extending up,- ward from the bottom electrode, or plate, B through an insulating tube e of fused silica, or other suitable material, and connected, by a carbon, or graphite, bridgepiece B to the top plate B of the next pile of electrodes, or plates, as clearly shewn in the drawings, only the first connection E, (the positive-connection) and the last connections E (the negative connection) being carried to the outside of the tank A, and connected with the source of electricity. F is the inlet for outlet (controlled from the space 0; A is the outlet for gas.

The tank A, is preferably made of iron enamelled inside and coated, or covered, in any suitable way, with heat-insulating material, (such, for example, as kieselguhr,) or adapted to be heated externally as explained in the specification of my aforesaid application Serial No. 551,306, of 1922 for Letters Patent. The said tank should be by the valve it) for metal electrically connected (as shown ate Figure 1) with the last negative electrode, or plate, of the series of piles so that only cathode effect, and no anode effect, can take electrolyte and H is 'the or plates B, B B has a cenat the bottom of the tank.

the escape of the products. The holes by which the gas passes upwards and the metal passes downwards are respectively marked 6 and b .On the said electrodes, or plates, may be provided with projections on, and recesses in, the faces opposed to each other in the pile. Such projections and recesses may, for example, be rectangular pyramidal formations depending from the lower surface of the electrode, orplate, and entering, to the requisite extent, the corresponding depressions, or hollows, in the upper face of the electrode, or plate, each projection corresponding with a similar recess, so that the whole, when in place in the pile, forms a very extensive surface for the electrolytic action. For instance, electrodes, or plates, two inches in thickness and twelve inches square may each be provided with a hundred and forty-four such recesses, one inch deep, in the upper face, each recess being at the surface of the electrode or plate, bounded by a rectangle one inch on each of its four sides, whilst, at the lower surface of the electrode, or plate, there are one hundred and forty-four corresponding pyramidal projections one inch high. At the apex of each pyramidal projection and at the bottom of each recess are thesmall holes to allow of the deposited metal draining downward, the gaseous products passing upward by similar holes at the corners of the pyramidal projections.

To secure economy in electrical energy, it is advantageous to fit the insulating sheets a closely all round and below the piles of electrodes, or plates, B, B B and also to avoid badly fitting joints, or open spaces, and to restrict all communicating passages where leakage of current might pass; for example, the holes b in the electrodes, or plates, and also the drain-oflf holes, or tubes 6 for the metal, in the insulating base-plate a at the'bottom of the piles, should be restricted to the smallest practical sectional area and the electrodes, or plates, B, should be thick in comparison with the spaces between them. I may, for instance, employ plates one inch, or two inches, thick separated by spaces threeeighths of an inch across and pierced by holes one quarter of an inch in diameter for draining oil the metal and one-eighth of an inch in diameter for the escape of the gaseous product. In this way I can secure very high current etliciency for my apparatus and process and a maximum of effect for a minimum of electric energy consumed. A

singletank apparatus of this kind, of but moderate dimensions, is capable of absorbing the whole output of a large electric generator. I

Referring now to Figures 4:, 5 and 6, these illustrate amodification of the construction of the apparatus, wherein I ar- -tween any two adjacent pla or holes, af, and the passages (1",

range the electrodes, or plates, B, in a vertical, or approximately vertical, position in one, or more than one, multiple-couple electrolyzers, or piles, which, or each of which, I will refer to as a series. When two, or more, series are used, they will preferably be placed parallel with each other so as to constitute two, or other number, of rows of multiple-couple electrolyzers, or piles. Although I shew the plates arranged quite vertically it is to be understood that I may if desired, incline them somewhat from the vertical so as to facilitate "thevdownward passage of the metal and the upward passage of the gas without the gas and the metal coming into contact with each other and recombining.

The electrodes, or plates B, are carefully fitted into grooves a in the insulating material a, at the sides and at the bottom into grooves a", in the bottom lining which is preferably made up of blocks of glass, porcelain, fused silica, or the like, a", all being arranged so that as tight a seal as possible is formed against electric leakage at the sides and lower edges of the plat-es B, whilst the upper edges of. the said plates can be similarly sealed by means of a bar of insulating material B extending between the sides of the tank, and above the top of the electrolyte and for a suliicient distance (say, for instance from one to two inches) above the upper edges of the plates B, as seen clearly in Figure 6, so that, whilst the plates B can be completely immersed in the electrolyte, yet the level of the electrolyte, (indicatcd by the line 0) will not rise to such a height as to make electric communication between the cells. The plates may terminate at bottom at I), and be continued by an approximately triangular piece B of nonconducting material to guard against the clogging of the outlets for separated metal. A single series, or each single series, of such plates B in a longitudinal tank may consist, for instance (as in the example illustrated) of sixty plates, each say from one half of an inch to one inch, or more, in thickness and separated by spaces of say three-eighths of an inch. The space bes therefore constitutes what may be termed a more, or less separate cell filled with electrolyte and the surfaces at the bottom of such spaces, below .the bottom-of the plates, slope (preferably from each side towards the middle as shewn in Figure 6) towards the hole a (or holes) for the passage of the produced metal into a collecting channel a" extending lengthwise of the apparatus and sloping towards one end, as shewn in Figure 5, (or it may be towards each end,) and terminating at the end, (or at each end), in a well -D, for the collection of the fused metal.- The hole, are, in the construction illustrated, in the solid insulating bottom part a The holes a, should be as long as isconvenient in order to de-- crease, as much as may be, the passage of leak current from cel v to cell by way of these holes. In each plate there is, at top and bottom, a hole, or passage, (or-there may be several. such holes, or-passa es,) communicating with the next cell. uch

holes, or passages, are marked respectively I) and b and where there are single holes,

or passages, one at top and one at bottom, as illustrated, they are preferably staggered, that is if the hole in one plate be near the upper left-hand side the hole in the next plate will preferably be near the Lower right-hand side, and so on throughout the series.

The well, or each well, D, into which the sloping channel a underneath the series of cells, or each series of cells, opens, as foresaid, has its walls extended to the upper part of the apparatus as seen clearly in Fig ure 5 and then the well, or wells, in addition to being employed for receiving the metal can be used for passing in the fused electrolyte, a hole, or passage, or holes, or passages, being provided in the end plate B (indicated at 6 for the passage of the electroyte from the well, or Wells, into the first cell.

The end plates B and B are insulated from the tank A by insulating material 9 and, as the end plates of the series of plates 2 are respectively connected with the positive and negative poles of the generator, or other source of electrical supply, the electric current passes from space to space between the plates throughout the series. The arrangement and connection of the single series, or the two, ried; for instance, as in the example illustrated, the plate B, at the end of the first series can be extended laterally to constitute an end plate for the next series and the middle end plate B of that series can be similarly extended to the third series and similarly with the other plate B and the fourth series the series being parallel and separated from each other by the insulating partitions a which form the separating walls of the several series of plates B, the electric current passing along each series and from series to series to the end thereof and the electrolyte passing in the example illustrated through the spaces between each series of .plates and by an opening, or openings, 6

from series to series and so on with any desired number ofseries, each comprising any desired number of plates. Four such series of 60 couples each can, for instance, be worked at say from 400 to 500 volts.

There may be a well D, for each series, or a well common to more than one series and the well, 01' Wells, may be in any suitable po- .several series of plates illustrated, passes down between or more, series, can be va-.

sition, the channel, or channels, for leading the metal thereinto being inclined downward to the well, or wells. The electrolyte can be poured into the'upward extension from the well, or from the first of the wells, above the metal therein, fected, through an inlet F from any suitable source, the said electrolyte then through the hole 6 and taking a zigzag course, through the staggered holes 6, b in the plates, plates and, in the example illustrated, successively throughout the first, second, third and fourth, series.

The insulating divisions a between the B, may be grooved to receive the plates. The apparatus may be formed with separate tanks A, for each series of couples, the said tanks communicating at the ends space G, above the plates, (which is, or may be, common tothe series, or to the two, or more, series) is enclosed by the cover A, for the collection of the gas which is given off at one side of each plate and an escape, such as is shown at A,

and up and down between the where two series join. The

is provided for the gaspassing to anysuitable place for collection, orutilization, as may be desired.

The metal separated by the electrolysis, in apparatus in accordance with the example theplates B, B4 and B through the holes a and chan-' nels a into the wells D, from each of which it can, when required be run by opening the valve in, controlling the outlet H, of any one of the-wells.

The modified arrangement described constitutes a very eflicient and readily constructed electrolyzing apparatus which has the advantage that, if an electrolyte, somewhat impure as regards the desired product, be fed into one end of the apparatus it will, after traversing the series of couples, become greatly purified and, in the example instanced, the desired product can eventually be obtained completely, or practically completely, pure, whilst product of the lesser purity obtained from the first, or earlier, series can, when so desired, be removed from the well appertaining to that series and be employed for any purpose where extreme purity is not requisite.

This modification of the apparatus is calculated to secure, to a further degree, efficient insulation of the couples and series of couples and so reduce to a minimum leakage of current and further ensure high current efficiency even at very low voltage. Slow circulation of the electrolyte through strictly limited passages from end to end of the. apparatus is also further ensured and also the collection of' the produced metal in two, or more, separate portions is facilitated by the employment of separate passages and wells collecting from each series in one apparatus.

- electrode groups arranged therein, the elec- I do not limit myself to the number, or the shape and dimensions, of the electrodes, or plates, in each component electrolyzer, or pile, nor nent electrolyzers, or piles, combined in one apparatus according to my present invention.

What I claim is U 1. Electrolytic apparatus comprising a container for fused electrolyte, a series of electrode groups arranged therein, the electrodes of each group electrolyte under operating conditions and spaced apart to form a plurality of electrolytic couples arranged in electrical series, partitioning of insulating material which electrically isolates the respective electrode groups and closely confines the margins of--.

the electrodes in such groups to minimize current leakage between groups and between electrodes of each group through the fused electrolyte.

2. Electrolytic apparatus comprising a container for fused electrolyte, a series of electrode groups arranged therein, the electrodes of each group being immersed in the electrolyte under operating conditions and spaced apart to form a plurality of electrolytic couples arranged in electrical series, partitioning of insulating material which electrically isolates the respective electrode groups and closely confines the margins of the electrodes in such groups to minimize current leakage between groups and between electrodes of each group through the fused electrolyte, together with means common to the several groups for gathering above the surface of the electrolyte the gases resulting from electrolysis of the melt.

3. Electrolytic apparatus compijising a container for fused electrolyte, a series of electrode groups arranged therein, the electrodes of each group being immersed in the electrolyte under operating conditions and. spaced apart to form a plurality of electrolytic couples arranged in electrical series, partitioning of insulating material which electrically isolates the respective electrode groups and closely confines the margins of the electrodes in such groups' to minimize current leakage between groups and between electrodes of each group through the fused electrolyte, together with means at the bottom of the container for the reception of fused metal resulting from electrolysis, and restricted outlets thereto from the electrolytic chambers.

4:. Electrolytic apparatus comprising a container for fused electrolyte, a series of trodes of each group being immersed in the r electrolyte under operating conditions and spaced apart to form a plurality of electo the number of such compo-' being immersed in the container for fused electrolyte,

tween piles and between partitioning of insulating material which electrically isolates the respective electrode groups and closely confines the margins of the electrodes in such groups to minimize current leakage between groups and between electrodes of'each group through the fused electrolyte, together with means for connectiiig said groups in electrical series.

5. ectrolytic apparatus comprising a container for fused electrolyte, a series of electrode groups arranged therein, the electrodes of each group being immersed in the electrolyte under operating conditions and spaced apart to form a plurality of electrolytic couples arranged in electrical series, partitionin of insulating material which electricafiy isolates the respective electrode groups and closely confines the margins of the electrodes in such groups to minimize current leakage between groups and between electrodes of each group through the fused electrolyte, together with means above the level of the electrolyte for connecting said groups in electrical series.

6. Electrolytic apparatus comprising a a series of electrode piles arranged therein, the electrodes of each pile being immersed in the electrolyte under operating conditions and superposed but spaced apart to form a plurality of superposed electrolytic couples arranged in electrical series, partitioning of insulating material which electrically isolates the respective electrode piles and closely confines the margins of the electrodes in each pile to minimize current leakage between piles and between electrodes in each pile, and means for connecting the several piles in series, said means comprising a fee connection to the top electrode of one pile and a jumper connection from the bottom electrode of that pile to the top electrode of another pile, and means isolating said jumper connection from the electrolyte and the upper electrodes of the first pile.

7. Electrolytic apparatus comprising a container for fused electrolyte, a series of electrode piles arranged therein, the electrodes of each pile being immersed in the electrolyte under operating conditions and superposed but spaced apart to form a plurality of superposed electrolytic couples arranged in electrical series, partitioning of insulating material which electrically isolates the respective electrode piles and closely confines the margins of the electrodes in each pile to minimize current leakage beelectrodes in each pile, and means for connecting the several piles in series, said means comprising a feed connection to the top electrode of one pile and a jumper connection from the bottom electrode of that pile to the top electrode of another pile, and means isolating said .per surface.

jumper connection from the electrolyte and posed electrode, said several electrodes be the upper electrodes of the first pile, said mg perforated in r means comprising an insulating conduit the hills and th passing through the upper elect-rodes of said the b first pile. forated only in registe 8. In an electrolyzer, an electrode having which a hill and valley surface contour, and pervalleys foratcd in register with the crests of the hills 15. In an electrolyzer spaced electrodes, th 9. In an electrolyzer, an electrode having the top and bottom a hill and valley contour on both upper and and valley contou lower surfaces, the hills of the upper sur-' lower surfaces, face coinciding with the valleys of the lower face of one ele surface, the body of the electrode being pervalleys of the forated in register with the crests of the posed electrodes, ing perforated i 10. In an electrolyzer, an electrode having the hills and the top electrode of lower surfaces, the hills of the upper suronly in register facecoinciding with the valleys of the lower pass through surface, the body of the electrode being-perface hills of the sub forated in register with the crests of the hills bottom electrode of t and the bottoms of the valleys, and the pcrated only in register wit forations which register with. the crests of which pass th the hills of the upper surface being of less valleys of the diameter than the perforations which regis- 16. In an ele ter with the bottoms of the valleys of the upspaced electrodes,

, the top and bottom elect 11. In an electrolyzer, an electrode havlng and valley contour for th a hill and valley surface contour, and p err urf c th hill of th forated in register with the crests of the h1lls one electrode registering and the bottoms of theva1leys,s'aid electrode the lower surface of th being pierced to accommodate an insulating trodes, said several elect conduit passed therethrough. rated 12. In an electrolyzer, a pile of superposed and th spaced electrodes, the electrodes intermeelectrode of the diate the top and bottom electrodes having i register wit hill and valley contours for their upper and pass through lower surfaces, the hills of the upper sur-, face .hills of face of one electrode registering with the bottom electro valleys of the'lower surface of the supert d l i posed electrode, said several electrodes being which pas perforated in register at the crests of the ll y f th hills and the bottoms of the valleys. with 13. In an electrolyzer, a pile of superposed th b ttom 1 spaced electrodes, the electrodes intermediate electrodes of the pile. the top and bottom electrodes having hill 17. In an electrol and valley contours for their upper and spaced electrodes, t lower surfaces, the hills of the upper surthe top and bottom 1 ace of one electrode registering with the and valley ontour f valleys of the lower surface of thesuperlower surfaces, the hi1 posed electrodes, said several electrodes beface of one ele ing perforated in register at the crests of valleys of the l the hills and the bottoms of the valleys, posed the top electrode of the pile being perforated ing perforated i only in register with the perforations which the hills and the pass through the crests of the upper surtop electrode of and the bottoms of the valleys.

hills and the bottomsof the valleys.

a hill and valley contour on both upper an face hills of the subjacent electrode. 7

ottom electrode pass throng of the superjac gister at the crests of th the valleys, the top pile being perfora h the perforation the crests of the u the subjacent else do of the pile bei register with the per 0 through the upper superjacent electrode, lating conduit extendi ectrode throu e bottoms of only in register w l4.-In an electrolyzer, a pile of superposed pass through the spaced electrodes, the electrodes intermediate hills of the subj the top and bottom electrodes having hill electrode of the and valley contours for their upper and in register with thepe lower surfaces, the hills of the upper surthrough the upper s face of one electrode registering with the superjacent electrode, va l y of the l wer surface of: the supersulating' conduit exten egistcr at the crests of e bottoms of the vall of the pile: being r with the perforations h the upper surface ent electrode.

a pile-of superposed e electrodes intermediate 1 electrodes having hill rs for their upper and the hills of the upper surctrode registering with the er surface of the supersaid several electrodes be 11 register at the crests of bottoms of the valleys, the the pile being perforated .with the perforations which the crests of th Y per e upper surjacent electrode, the

ile being perforthe perforations rough the upper surface superjacent electrode.

pile of superposed odes intermediate rodes having hill eir upper and lowe upper surface of with the valleys of e superposed elecg perfoe hills ted only s which pper surtrode, the

perforations surface together ng from gh the superposed a pile of superposed ctrodes intermediate ectrodes having hill or their upper and ls of the upper sur-' g1stering with the ower surface of the supersaid several electrodes be 11 register at the crests of bottoms. of the valleys, the the pile being perforated ith the perforations which crests of the upper surface acent electrode, the bottom being perforated only rforations which pass urface valleys, of the together with an in 13 ding from the bottom 0 6 v I 1,545,384" A electrode through the su erposed electrodes name to this specification in the presence of of dthe pile, ant}1 a conductorbarranged iln two subscribing witnesses. sai .con uit an exten in a ove t e pi e to afford means for estaglishing a series EDGAR ARTHUR ASHOROF'I' 6 connection to the top electrode of-another Witnesses: v

-pi1e. GImEBT Fm'rolmn TYs'oN; In testimony whereof I have signed. my LEONARD WAIIIER. 9 

